This project investigates how rhesus monkeys and other primate species born and raised under different laboratory conditions adapt to placement into naturalistic outdoor environments and compares this adaptation process to that seen in natural settings and in indoor environments that contain specific physical and social features of the monkeys' natural habitat. Adaptation is assessed by examining behavioral repertoires and by monitoring a variety of physiological systems in these subjects, yielding broad-based indices of relative physical and psychological well-being. During FY90 detailed longitudinal comparisons were continued between members of a small multigenerational troop of rhesus monkeys living in a 5-acre outdoor enclosure and members of a second multigenerational group maintained in indoor settings over a comparable period. Detailed analyses of play behavior exhibited by infant and juvenile group members yielded species-normative age and sex differences in the amount and type of play, as well as interactions with the type of housing environment. A new procedure for feeding group-housed rhesus monkeys that resulted in favorable changes in activity cycles and specific behavioral and physiological changes, as well as reducing expense and caretaker staff time, was developed and implemented. Special foraging devices were also utilized to generate new tests of spatial memory and observational teaming in both rhesus monkey and Cebus apella groups. A comparative developmental study of vocal behavior of Cebus apella in field and captive environments was initiated, and analysis of vocal behavior and spatial structure in natural populations of two species of squirrel monkeys was continued. Finally, in collaboration with DRS scientists, an inexpensive enrichment device for singly housed primates was developed and tested, resulting in significant, long-term reduction of abnormal behavior patterns.